The present invention relates to the field of image processing. More specifically, the invention relates to a method and apparatus for improving the signal-to-noise ratio of an image during image processing.
Conventional treatment of vascular diseases is done by open surgery procedures. In open surgical procedures, the diseased area is exposed and then operated upon. This leads to patient discomfort. A rapidly emerging alternative to open surgery is endovascular interventional procedure. Endovascular interventional procedure is preferred to the conventional open surgery procedure because it is minimally invasive. Further, the duration of the patient's stay in intensive care is shorter, the blood loss is less, and therefore the cost effectiveness is higher.
In endovascular interventional procedures, the surgery is carried out through a puncture on the surface of the patient's body. The surgery of the region of the vascular disease is achieved by a flexible tube called catheter, which is introduced through the puncture into an artery or into a vein. The catheter is then moved to the region where the vascular disease is present. The movement of the catheter to the intended position is done with the help of a “guide wire”. During the surgery, the surgeon is not able to directly view the instruments since the entire procedure is carried out within the body. One of the most common methods of dynamically tracking the guide wire and the catheter inside the body is X-ray fluoroscopy. In this procedure, a contrast agent is introduced in the in the patient's body either through injection or through ingestion. The role of the contrast agent is to block the passage of X-rays and thus help in visualization of that part of the body where the contrast agent is located.
In a typical endovascular interventional procedure performed under X-ray fluoroscopy, it is critical that the surgical instruments like the catheter and the guide wire are accurately positioned at their intended location. The accurate positioning of the surgical instruments requires the surgeon to have a very accurate tracking of the catheter and the guide wire. For accurate tracking of the surgical instruments, high quality X-ray fluoroscopy images of the location of the catheter and the guide wire are needed.
Typically, the X-ray fluoroscopy images are of low quality and this is due to several factors. One is the low strength of the X-rays used; the strength of the X-rays is kept low to minimize the harmful effects of the X-rays. And, this is done as the duration of exposure to X-rays in an X-ray fluoroscopy procedure is very long. Another factor that affects the quality of the X-ray images is the motion of the catheter and the guide wire. This motion is caused because the X-ray reading device has to continuously adjust its position in order to follow the movement of the catheter and the guide wire. Due to the above mentioned factors, the surgeon might not be able to see the surgical instruments in all the low quality X-ray images.
As described above, there is a need for accurate tracking of the catheter and the guide wire in an X-ray fluoroscopy procedure. Improving the quality of the X-ray fluoroscopy images will lead to a significant improvement in the ease with which the surgeon is able to track various surgical instruments. The quality of an image can be improved by processing the image to increase the signal to noise ratio of the image. Thus, there is a need for improving the signal-to-noise ratio of an image during image processing.